川东北龙会场-铁山地区飞仙关组层序地层划分

Stratigraphic sequence classification of Longhuichang-Tieshan area in Northeast Sichuan

川东北龙会场—铁山地区在飞仙关期飞二段发生相变,导致T1f1-T1f3地层不易对比划分,前人划分层序标准不一,致使无法精细刻画沉积相展布范围。运用层序地层学的理论,以最大海泛面为依据,确定长兴组和飞仙关组的分层界面,以沉积旋回为表示方法,从岩性、电性上进行对比,将飞仙关组从下至上划分为5个沉积旋回,并建立地层层序格架进行对比分析,在等时单元内对沉积相带进行精细刻划,为正确认识有利微相在等时格架内的纵横向分布奠定坚实的基础。

The phase change of the 2nd member of Feixianguan formation in Longhuichang-Tieshan area led to great difficulty in stratigraphic classification and correlation of T1f1~T1f3.As there are different standards in stratigraphic sequence classification,the sedimentary facies distribution range can not be accurately described.By using the theory of stratigraphic sequence,taking the maximum flooding surface as the guidance,the stratified interface between Changxin formation and Feixianguan formation has been determined,and the depositional cycle has been taken for representation.From the correlation of lithology and electrical property,5depositional cycles have been classified from the bottom to the top of Feixianguan formation,the stratigraphic sequence framework has been established to carry out comparative analysis,and fine description of sedimentary facies belt has been conducted within the isochrono-stratigraphic units,which lays a solid foundation for good recognizing lateral and vertical distribution of favorable microfacies within the isochrono-stratigraphic units.